Material hoist and fall arresting devices have been used for years for raising and lowering materials and retrieving stricken personnel from enclosed vessels. However, when such materials and personnel must access the vessel through a manway located in the side of such vessels, a great many problems arise. The primary problem being, how to achieve a mounting for hoist and fall arresters which will not impede access via the manway. Should the manway become blocked or impeded in any way, vital time could be lost when attempting to extract injured personnel. The same would be true if the fall arrester blocks the flow of materials through the manway.
One such device designed to overcome these problems has been disclosed by Olson et al. in U.S. Pat. No. 5,147,013. The Olson device provides a tripod arrangement, mounted on brackets which are further mounted to the manway cover flange. The Olson apparatus is dependent upon both upper and lower support members mounted on the manway. This arrangement is further dependent on a specific size of manway requiring adapters and the like which would further restrict access through the manway due to the horizonal mounting of the fall arrester and the location of the lower mounting member. The use of an outside roller mounted on the lower member, as described by Olson, is of no consequence since a working platform would normally be constructed just below the manway and would thus prevent the lowering of personnel or materials. The platform, extending into the vessel from the lower support as claimed by Olson, would also impede the decent of personnel attempting to climb down a ladder attached to the vessel wall. Olson further fails to provide a means for extending or retracting the tripod. Therefore, it would seem impractical to lower or hoist material directly over the worker and his only means of retrieval. Problems would also exist if an injured worker was being raised in an emergency situation whereby the tripod was extended some distance towards the center of the vessel. It would be extremely difficult to reach and retrieve the worker from the manway.
A fall arrester apparatus is also disclosed by Olson et al. in U.S. Pat. 4,589,523. Olson describes the structure and use of a tripod frame and arrester winch mechanism suspended over a vessel having a top mounted manway. There are several fundamental differences between the apparatus disclosed by Olsen and that of the present invention. The tripod arrangement of Olson has no means of attachment to the manway and is not intended for use inside the vessel. In this patent Olson concentrates on the fall arrester apparatus itself and its use in conjunction with the tripod frame. The arrester further depends on the frame for its mounting and support. The Olson apparatus is not adaptable for use inside the vessel and makes no provision for anchoring the arrester to the vessel in any manner.
It is, therefore, an object of the present invention to overcome the afore mentioned problems and provide a safe means for extracting personnel from an enclosed vessel having side access manways.
It is another object of the present invention to provide a more stable, quadruped structure for external vessel mounting which is adaptable to a tripod arrangement for inside mounting.
It is another object of the present invention to provide a universal mounting bracket, not dependent on the frame work for its support, which will receive most existing fall arresting and retrieval apparatuses.
Another object of the present invention is to provide a universal combination, fall safe mounting stand arrangement which works equally well for vessels with either side or top manways, regardless of the manway size.